Ah, I love these threads. Think of "embedding" - the man the dog bit died. Then think of multiple embeddings - the man the woman the dog the cat bit knew married died. Even OK rules can lead to un-OK solutions if misapplied. What is possible is not always feasible, to use Jargon. And while I'd heard "what did you bring that book I didn't want to be read to out of up for" I hadn't heard it with the added Down Under, which unfortunately are grammatically, I believe, nouns in that sentence... still, very good updating!